It has become commonplace to use computers to search large collections of content. Moreover, the types of searchable content are becoming more diverse. While search practices for various types of content have become established, search practices for some types of content can be inefficient, fragile and/or otherwise unsatisfactory. For example, it is not uncommon to search for interesting portions of a text document by specifying a string of alphanumeric characters. However, an attempt to search a collection of images by specifying a string of alphanumeric characters can have unsatisfactory results. Searching a collection of content by specifying query content (e.g., searching the collection of images by specifying a query image) can resolve some issues, but it can also raise new issues.
For example, query content creation can be an issue. Alphanumeric query strings can be specified using a standardized keyboard, but query images may be created under a wide variety of conditions (e.g., distance, angle, lighting, focus, digital resolution) that affect query image quality. As content types become richer, the usefulness of exact matches can decrease. However, the use of inexact matching allows for false positive matches, and the use of low quality query content can raise the false positive match rate to a problematic level.
Some aspects of query content quality can result in failure to find a match, even when a useful match exists and the query content is of relatively high quality. For example, a search facility may fail to find a match for a relatively high quality digital photograph of an object, even where the collection of content includes images of the object, if the query image is taken from a perspective too dissimilar from the images in the collection. As another example, the object may have relatively few distinguishing features, so that even relatively slight flaws in query content quality can be problematic.
Same numbers are used throughout the disclosure and figures to reference like components and features, but such repetition of number is for purposes of simplicity of explanation and understanding, and should not be viewed as a limitation on the various embodiments.